Treatment of cork.



K Metre 2a,!

fihh iifid PATENT @FFIWE.

FIRM F ARMSTRONG CORK AND INSU LATION COMPANY, OF PITTSBURGH, PENN-manta Sept. as, 1015.

SYLVANJLA.

TREATMENT OF CORK.

1355357. Specification of Letters Patent.

No Drawing. Application filed June 30, 1915. Serial No. new.

To all whom it may concern:

Be itknown that 1, Max GRUNZWEIG, Dr. ling, citizen of the GermanEmpire, and residentof Ludwigshafen on the Rhine,

5 Germany, have invented new and useful improvements in the Treatment ofCork, of which the following is a-specification.

Applicant has shownin his prior Patent No. 997050 that cork may beexpanded by' heating it to high temperatures, preferably above 200 C. Ithas been found that the expansion of cork may be obtained not only byraising its temperature considerably, but by utilizing other agents atthe same time.

If cork contains a certain degree of moisture, as the cork of the tradealways does, the evaporation of the water contained in the cork cellulestends to expand the same. The energy of expansion is increased if thecork is heated as rapidly as possible, approaching the point where theevaporation is effected in the manner of an explosion.

The apparatus used hitherto for heating cork, such asrevolving furnaces,and the like, retain the cork for a relatively extended length of time;and the desired maximum temperature is reached in amoderately quick way.That is the reason why the pressure insidethe cellules of the cork isweak and the expansion isnot carried to its maximum. If however, theheating lasts only'a half a minute to five minutes and the cork is moistenough, a considerable increase of volume may be attained at a'temperaturelittle above the ebullition point of water, an expansionwhich was hitherto possible only at temperatures above 200 C. becausethe pressure of steam is considerable at temperatures between 100 C. and150 C. In orderto heat the cork in so short a time up to a temperatureof from 100 C. upward, the heatmust be imparted to the cork particlesvery energetically. This may be done by using an atmosphere of veryconsiderable temperature; for example the .cork' may be brought into achamber of a temperature of 1000 C. and be removed again at once. Inorder that the cork is not carbonized or ignited it should be agitated;the more vigorous the agitation the better the result.

The cork may of course be heated up to the permissible maximum of about400 C.

The cork thus expanded may be .used in known way to form cork stone withor without a cement, as loose fillingmaterial and the like. 7 l Now whatI claim and desire to secure by Letters Patent is the following: a

l. A method to increase suddenly the volume of cork particles attemperatures above 100 C.' which consists in heating the cork suddenlyto the said temperatures. I

2. A method to increase suddenly the volume of. cork particles attemperatures above 100 C. which consists in placing sufliciently moistcorkparticles in a chamber previously highly heated and agitating thecork.

3. The method of expanding cork particles which consists in suddenlyheating them toa temperature below 200 C.

That'I; claim. the foregoing as my invention, I have .signed'my nameiii-presence of two witnesses, this seventh day. of June A. D.

MAX GRUNZWEIG. Witnesses CARL Mrsnn, C. INNans'BnowN.

